Rejection type fuse clip and cartridge fuse assembly

ABSTRACT

A rejection type fuse clip and fuse assembly wherein each of the caps of the fuse includes a cylindrical contact surface engaged by the cooperating contact surface of a fuse clip, and annular end surface, a cylindrical projection extending axially outwardly from said annular end surface and having a smaller diameter than said cylindrical contact surface, and a circular end surface closing the axially outer end of said cylindrical projection.

United States Patent X X X X (2U 8 ll) oo 5 43 x233! n3 n33 7 R 7 5 3 3 2 3 3 w 3 3 an" 3 u m m m m C a u" N m mm m m nuflnunlu R nuuuuua "E mm mll W sn kkhsE Yn CC i e oo WS T U 6 0 000 E MLSWKKPM 540042 70 66665553 99999999 llllllll ll/l/l/l 3 622467 559oo5 7 2390 82 J 383404 6 7 427953 33222222 0 N am o 0 on n m .c. a E m. w m 3 C mm H t um N m m wM 4 WM 9 M m i Q MWS MM m 1... M mm h s) 7 uuu w J.e w3 nfl l wmo O H I. 7 KNBAJTNC7 0 e m N m m n L n m m W pun ms I. AFPA 111]] 2 253 7 2247 .l [[[l Fritz Driescher Kg. (W. Germany) Advertising Brochure Primary Examiner-Bernard A. Gilheany Assistant ExaminerDewitt M. Morgan Attorney- Erwin Salzer CARTRIDGE [54] REJEC'I'ION TYPE FUSE CLIP AND FUSE ASSEMBLY 8 Claims, 13 Drawing Figs.

tending axially outwardly from said annular end surface and. having a smaller diameter than said cylindrical contact sur- [56] References Cited UNITED STATES PATENTS 3,246,106 4/1966 Sommers......................

face; and a circular end surface closing the axially outer end of said cylindrical projection.

f a 0 m PATENTED JUN 1 5 IQYI SHEEI 1 BF 3 FIG. 2

INVENTOR: v I KENNETH W. SWAIN T MA ,A TY

PATENTEUJUNISIQTI 358555 I SHEEI20F31 INVENTOR:

KENNETH W. SWAIN BY )WWWMM ATTY.

PATENIEU JUN i 5 I971 SHEET 3 BF 3 FIG. IO

PRIOR ART Y --A RW, m8 WW H T E N N E K REJEC'IION TYPE FUSE CLIP AND CARTRIDGE FUSE ASSEMBLY 4 BACKGROUND OF THE INVENTION This is a continuation-in-part of my copending patent application filed Oct. 24, 1968; Ser. No. 770,317 for REJECTION TYPE FUSE CLIP AND CARTRIDGE FUSE ASSEMBLY which, in turn, is a continuation-in-part of my patent application filed Feb. 16, I968; Ser. No. 708,030 for REJECTION TYPE FUSE CLIP AND CARTRIDGE FUSE ASSEMBLY, both now abandoned. There are two general types of fuses commercially available in the United States of America, namely fuses having a normal interrupting capacity, and fuses which have a higher interrupting capacity than the aforementioned fuses, the latter being normally current-limiting. Both types of fuses have generally the same dimensions, the same axial spacing between their caps, and the same diameter of their caps for same current ratings. If a high interrupting capacityv current-limiting fuse were accidentally replaced upon blowing thereof by a fuse having a lower interrupting capacity, the replacement fuse might not be able to interrupt a major fault current occurring in the particular system. The

. fuse having the lower interrupting capacity may explode, causing serious damage to property and endanger life, or it may cause'i'nte'rru ption of the fault current by another interrupting device located nearer to the source of power feeding into the short circuit than the particular fuse. In the latter case a larger portion of the system is rendered inoperative than the portion which would have been rendered inoperative had the fuse properly performed its interrupting duty.

For the above mentioned reasons it is imperative to preclude insertion of fuses having a relatively limited interrupting capacity into fuse holders into which only fuses having a relatively high interrupting capacity should be inserted. The rejection-type fuse clips and coordinated fuse caps disclosed in US. Pat. No. 2,558,581 to A. L. Powell et al., June 26, 1951, COORDINATE FUSE AND MOUNTING CLIPS and in US. Pat. No. 2,943,295 to V. N. Stewart, June 28, 1960, REJECTION TYPE FUSE CLIP are widely used for precluding insertion of fuses having a relatively limited interrupting capacity into fuse clips inserted into circuits which require fuses having a relatively large interrupting capacity.

According to the above-referred-to patents the caps of high interrupting capacity fuses are provided with circular channels. Rejection abutments forming part of the fuse clips are allowed to entgr, or project, into these circular channels in the caps of high interrupting capacity fuses, thus allowing high interrupting capacity fuses to be inserted into such rejectiontype fuse clips. The caps of fuses having a relatively lower interrupting capacity are not provided with the aforementioned circular channels and, as a result, cannot be inserted into rejection-type fuse clips.

The above described system has two serious limitations. It is relatively difficult and expensive to manufacture caps for fuses which caps are provided with the circular channels. As a rule such caps are made up of two parts, i.e. a lateralwall part defining the circular channel, and an end part, or cover, for the lateral part. This end part, or cover, must be secured to the lateral part by such means as, for instance, soldering, which further greatly increases the cost of manufacture.

It happens quite frequently that the axial spacing of the rejection fuse clips mounted in a particular piece of equipment is not sufficiently precise to allow rejection abutments of the fuse clip to enter into the circular grooves in the fuse caps, and thus to accept the high interrupting capacity fuse. In such instances the high interrupting capacity fuse is rejected by the fuse clips, though it should be allowed to be inserted into the same. Such situations call for a readjustment or repositioning of the rejection-type fuse clips which is a time consuming process requiring skilled labor that may not be at hand under the circumstances requiring such an operation.

It is the primary object of this invention to provide a rejecabove limitations. I

While every precaution must be taken to avoid insertion of fuses having a relatively low interrupting capacity into circuits requiring fuses having a relatively high interrupting capacity, it is desirable to adapt high interrupting capacity fuses in such a way that they can be inserted selectively either into standard fuse clips, i.e. fuse clips intended to receive standard relatively low interrupting capacity fuses, or into rejection-type fuse clips, intended to receive only high interrupting capacity fuses. This requirement will become more apparent from a consideration of a typical situation outlined below.

Considering an industrial distribution system including many branch circuits that can be protected effectively by means of low interrupting capacity fuses and that includes also many branch circuits that require high interrupting capacity fuses for their effective protection. If standardlow interrupting capacity fuses and nonrejection-type fuse holders are inserted into the former circuits, and high interrupting capacity fuses and their rejection-type fuse holders are inserted into the latter circuits-thus conforming with widely adopted current fusing practice-the maintenance of the distribution system becomes rather complex and difficult. The reason which may render such an up-to-date distribution system undesirable lies in the fact that its maintenance calls for two types of fuses for each current rating-i.e. relatively low interrupting capacity fuses and relatively high interrupting capacity fuses-and that it calls for different fuse clips for each type of fuses-i.e. standard fuse clips and rejection-type fuse clips.

It is another object of this invention to provide a system of fuses that can be established and maintained without the aforementioned undesirable duplication of parts.

SUMMARY OF THE INVENTION A rejection-type fuse clip and fuse assembly according to the present invention includes a pair of spaced fuse clips each having a pair of fuse-cap-engaging contact surfaces. Each of said pair of fuse clips further includes a pair of rejection abutments of which each projects radially inwardly from one of said pair of contact surfaces. Each of said pair of rejection abutments has a smaller radial spacing than said pair of contact surfaces. Said pair of rejection abutments of said pair of clips have a predetermined axial spacing.

The assembly according to this invention further includes an electric high interrupting capacity cartridge fuse inserted into said pair of clips. Said fuse has a tubular casing of insulating material, a fusible element inside of the casing, and a pair of terminal caps conductively interconnected by said fusible element and mounted on the ends of said casing. Each of said pair of caps has a cylindrical contact surface engaged by said pair of contact surfaces of one of said pair of clips, an annular end surface, a cylindrical projection extending axially outwardly from said annular end surface, and a circular end surface closing the axially outer end of said cylindrical projection. Each of said pair of caps consists on one single, seamless piece of sheet metal. The axial spacing of the annular end surface of each of said pair of caps is slightly less than the predetermined spacing of said pair of rejection abutments of said pair of clips, allowing said pair of rejection abutments of said pair of clips to overlap said annular end surface of each of said pair of caps. The diameter of said cylindrical projection of each of said pair of caps is smaller than the diameter of said cylindrical contact surface of said pair of caps and sufficiently small to allow insertion of said fuse into said pair of clips without interference of said cylindrical projection of each of said pair of caps with said pair of rejection abutments of said pair of clips.

BRIEF DESCRIPTION OF THE DRAWINGS.

FIG. 1 is a vertical section of a fuse clip and cartridge fuse assembly embodying this invention taken along H of FIG. 2;

FIG. 2 is a side elevation of the structure of FIG. I;

FIG. 3 is a top-plan view of the structure of FIGS. 1 and 2, and

FIG. 4 is a vertical section of a modification of the top portion of the fuse according to FIG. 1;

FIG. 5 is a side elevation of a modification of the fuse shown in FIGS. 1-4, inclusive, inserted into a standard, i.e. nonrejection fuse clip;

FIG. 6 is a top-plan view of the structure of FIG. 5 seen in the direction of the arrow R of FIG. 5;

FIG. 7a is an isometric view of a modification of the structure of FIGS. 3 and 4 and shows but one single end of a cartridge fuse supported by a fuse clip, the opposite identical and identically supported end of the fuse being deleted in FIG. 7a;

FIG. 7b is an isometric view of a detail of the structure of FIG. 7a.

FIG. 8 is an isometric view of one end of a cartridge fuse supported by a fuse clip, the opposite identical and identically supported end of the fuse being deleted in FIG. 8;

FIG. 9 is an isometric view of a modification of the structure of FIG. 8 drawn in the same fashion as FIG. 8;

FIG. 10 is a side elevation of a fuse which is a modification of that shown in FIGS. 5 and 6 inserted into standard fuse holder;

FIG. 11 is a side elevation of a standard or NEMA fuse inserted into a fuse holder intended for receiving such a fuse; and

FIG. 12 is a top plan view of the structure of FIG. 10.

DESCRIPTION OF PREFERRED EMBODIMENTS OF INVENTION Referring now to the drawings, reference character C has been applied to generally indicate a pair of spaced fuse clips and reference character F has been applied to generally indicate a high interrupting capacity current-limiting fuse. Each fuse clip' C is substantially U-shaped (FIG. 3) and has two flange portions which form a pair of fuse-cap-engaging contact surfaces 1. Each fuse clip C includes a pair of rejection abutments 2. Each of said pair of rejection abutments projects radially inwardly from the aforementioned pair of contact surfaces I. Rejection abutments 2 may be formed by radially inwardly bent portions of the flanges of clips C, or by an additional part, as more fully set forth in the above-referred-to U.S. Pat. No. 2,943,295. The radial spacing r between rejection abutments 2 is smaller thanthe radial spacing D between the fuse-cap-engaging contact surfaces I of fuse clips C. The pair of rejection abutments of clips C have a predetermined axial spacing S, thisspacing being measured between the axially inner end surfaces thereof.

The cartridge fuse F includes a tubular casing 3 of insulating material, a fusible element 4 inside of casing 3 and a pair of terminal caps conductively interconnected by fusible element 4. To this end the axially outer ends of fusible element 4 are bent around the rims of easing 3, and held in position by he pair of caps mounted on the end of easing 3. The bent ends of fusible element 4 are preferably conductively connected to the caps of the fuse by solder joints (not shown). Each pair of caps has a cylindrical contact surface 50 engaged by a pair of contact surfaces I of one of the pair of clips C, and annular end surface or shoulder 5b, a cylindrical projection 50 extending axially outwardly from said annular end surface or shoulder, and a circular end surface 5d closing the axially outer end of said cylindrical projection. Each of said pair of caps 5a, 5b, 5c, 5d consists of one single seamless piece of sheet metal. In other words, caps 50, 5b,5c,5d may be deepdrawn by conventional methods in a metal drawing press, but need not to be manufactured out of several parts, as generally done when manufacturing rejection type caps having a circular channel intended to be engaged by rejection abutments. The axial spacing of the annular end surface of each of said pair of caps is slightly less than said predetermined axial spacing S of said pair of rejection abutments 2 of said pair of clips C. This allows the pair of rejection abutments 2 of said pair of clips C to overlap said annular end surface, or shoulder, 5b of each of said pair of caps C. The diameter of the cylindrical projection 5c of each of said pair of caps 5a. 5b. 5c. 5d is smaller than the diameter D of the cylindrical contact surface 5a of each pair of caps 5a. 5b. 5c. 5d and sufficiently small to allow insertion of the fuse F into said pair of clips C without interference of said cylindrical projection 5c of each of said pair of caps 5a, 5b. 5c. 5d with said pair of rejection abutments 2 of said pair of clips C.

It is desirable to construct high interrupting capacity fuses in such a way as to make it possible to resort to various auxiliary means for maximizing the interrupting capacity thereof. Maximizing the interrupting capacity can be achieved in a number of ways. It is, for instance, possible to maximize the interrupting capacity by allowing products of arcing to flow out of the portion of the casing of the fuse which is filled with a pulverulent arc-quenching filler into an adjacent-void, or expansion chamber. A fuse structure embodying this principle is disclosed in U.S. Pat. No. 2,594,315 to Frederick J. Kozacka, Apr. 29, 1952 for CURRENT-LIMITING FUSE. Another method for maximizing the interrupting capacity of an electric fuse consists in allowing a high-pressure buildup during the interrupting process, which method is predicated on using a tubula'r casing having an increased wall thickness and on precluding outflow of products of arcing from the portion of the casing of the fuse which is filled with a pulverulent arcquenching filler. The structure embodying this invention allows to apply either of the two aforementioned methods for maximizing the interrupting capacity. i

As shown in FIG. 1 the casing 3 and the cylindrical projection 5c of the lower cap 50.. 5b. 5c. 5d is filled with a pulverulent arc-quenching filler 6, preferably quartz sand, and the cylindrical projection 50 of the upper cap 5a. 5b. 5c. 5d defines a void 7 separated by a partition 8 from the pulverulent arc-quenching tiller 6 inside of casing 3. Partition 8 may be formed by an asbestos washer allowing controlled leakage of products of arcing from the inside of casing 3 into the void in upper cap 5a. 5b. 5c. 5d. It will be apparent from the above that each terminal cap has an annular end surface or shoulder 5b situated between its axially inner cylindrical large diameter portion 5a and its axially outer small diameter portion 5c. The latter has a circular axially outer end surface 5d. As clearly shown in FIG. 1 the axial spacing of rejection abutments 2 from end surface 5b is relatively small, and may be virtually zero, and the radial spacing between each projection 50 and the adjacent contact surface I of the fuse clip 2 by which it is surrounded is relatively large.

FIG. 4 refers to a structure identical in every respect to that shown in FIGS. 1-3, and described in connection therewith,

except for the construction of one of the caps 5a. 5b, 5c, 5d,

i.e. the upper of the caps. As shown in FIG. 4 the cylindrical projection 5c of the upper cap 5a, 5b, 5c, 5d is filled with C. solidifiedinsulating material 9 precluding the pulverulent arcquenching filler 6 and products of arcing from entering into the cylindrical projection 5c of the upper cap 50, 5b, 5c, 5d. An asbestos washer 8 may separate the arc-quenching filler 6 from the body 9 of insulating material. The latter is preferably a relatively good thermal conductor.

In FIGS. 5-9 the same reference characters as in FIGS. 1- 4 have been applied to indicate like parts. Thus 3 designates the tubular casing, 5a the axially inner cylindrical surfaces of the terminal caps, 5b their annular end surfaces or shoulders, 50 their axially outwardly extending projections and 5d the cir cular end surfaces of projections 50. The fuse of FIGS. 5 and 6 is provided with a pair of annular adapters 10, one on each end, of which but one is shown in FIGS. 5 and 6. Each adapter 10 is frictionally mounted on one of cylindrical projections 50 and is in the form of a split ring to increase its resiliency. Reference character 10a has been applied to indicate a substantially radially extending slit formed in adapter rings 10. Adapter rings 10 have an inner diameter substantially equal to the outer diameter of cylindrical projections 50 and adapter rings 10 have an outer diameter substantially equal to the outer diameter of the cylindrical surfaces 5a of the terminal caps 50, 5b, 5c, 5d. In other words, the radially outer surfaces of adapters and the axially inner surfaces 5a of the terminal caps are flush. With adapters 10 mounted on terminal caps 5a, 5b, 5c, 5d the geometry of the fuse conforms to that of a standard fuse and it can readily be inserted in any pair of standard fuse clips such as, for instance, the fuse clip C' of FIGS. 5 and 6. No harm can result from inserting a high-interrupting capacity fuse into a pair of standard fuse clips forming part of a circuit whose available short circuit current is relatively low. The high interrupting capacity fuses are intended to be supplied to their user with adapter rings 10 mounted on both terminal caps 5a, 5b, 5c, 5d and can bereadily inserted into any standard fuse holders or fuse clips. Adapter rings 10 may, however, readily berernoved, or stripped, from projections 5c and then the fuses areready for insertion into rejection type fuse clips as shown in FIGS. 1-4, inclusive.

The fuse clip of FIG. 7a is made up of two separate parts including fuse-cap-engaging contact surfaces '1 abutting against surfaces 5a, and substantially U-shaped rejection abutmentsZ' small clearance from end surfaces Sb.

FIG. 7b shows a rejection abutment 2' removed from the fuse clip proper, i.e. the electrical contact surfaces 1 thereof.

FIG. 8 shows a fuse clip having widely spaced contact surfaces 1 engaging the surfacesSa of terminal caps 5a, 5b, 5c, 5d, and further having radially inwardly bent surfaces .2 whose spacing is less than that of cylindrical contact surfaces 1. The surfaces 2' have edges 2a adjacent the surfaces'5b of caps 5a, 5b, 5c, 5d whose clearance from surfaces 5b is extremely small.

Referring now to FIG. 9, the fuse clips have cylindrical contact surfaces 1 whose diameter is relatively large and engage the surfaces 5a of caps 5a, 5b, 5c, 5d.'The fuse clips furtherinclude cylindrical surfaces 2" whose diameter is relatively small and engage the projections 5c of terminal caps 5a, 5b, 5c, 5d. The surfaces 2" have edges 2a adjacent the surfaces'lib of terminal caps 5a, 5b, 5c, 511 whose clearance from surfaces 5b is extremely small. It will thus be apparent that the parts 2" of FIG. 9 have two functions, i.e. they are current carrying contacts and rejection abutments.

As set forth above in detail, no harm can result from the insertion of a high interrupting capacity into a pair of standard fuse clips forming part of a circuit whose available short circuit current is relatively low. Since high-interrupting-capacity fuses are shorter than standard fuses, insertion of high-interrupting-capacity fuses having pair of adapter rings 10 as shown in FIGS. 5 and 6 to allow their insertion into standard fuse clips C of an existing installation calls for a reduction'of the spacing of the fuse clips C to allow insertion of the highinterrupting-capacity fuses into them. This is an inconvenience which can be avoided by substituting the adapter rings 10 of FIG. 10 and FIG. 12 for the adapter rings 10-0 FIGS. 5 and 6.

In FIGS. 10 and 12 the same reference characters have been applied as in FIGS. 5 and 6 of designate link parts, except that reference character 10' has been applied in FIGS. 10 and 12 rather than reference character 10 to designate the adapter rings, and that reference character 10a rather than reference character 10a has been applied to indicate the substantially radially extending slits in the adapter rings. In the structure of FIGS. 10 and 12 each of the pairs of annular adapter rings 10' extends ina direction longitudinally of casing 3 beyond cylindrical projections 5c of terminal caps 5a, 5b, 5c, 5d to adapt the cartridge fuse of FIGS. 10 and 12 for insertion into a pair of standard fuse clips C having a spacing exceeding thespacing between the cylindrical projections 50 of caps 5a, 5b, 5c, 5d.

FIG. 11 shows a standard fuse F in a pair of standard fuse clips C having the proper spacing to receive the standard fuse F. It is apparent from a comparison of FIGS. 10 and II that due to the presence of special adapter rings I0 the fuse may be inserted into a pair of fuse clips C intended to receive a standard fuse without reducing the spacing of clips C. FIG. 11

- 20 I abutting agamst'annular end surfaces 5b,;or. having a very shows a fuse of standard size'and FIG. 10 has been drawn on the same scale as FIG. 11 and refers to a high-interruptingcapacity Class .I fuse.

The structure of FIGS. 1 to 4 shows rejection features on both ends of the fuse and on both cooperating fuse clips. It is, however, sufficient to provide rejection features on but one end of the fuse and on. but one fuse clip as clearly shown in FIGS. 5 to 9. v

It will be understood that I' have illustrated and described herein preferred embodiments of the invention, and that various alterations may be' made therein without departing from the spirit and scope of the appended claims.

Iclaim as my invention:

l. A rejection-type fuse clip and fuse assembly including a. a pair of spaced fuse clips each having a pair of fuse-capengaging contact surfaces, each of said pair of fuse clips further including a pair of rejection abutments, each of said pair of rejection abutments-projecting .radially inwardly from one of said pair of. contact surfaces, each of said pair of rejection abutments having a'smaller radial spacing than the radial spacing of said pair of contact surfaces, and said pair of rejection abutments of said pair of clips having a predeterminedaxial spacing; and

b. an electric high interrupting capacitycartridge fuse inserted into said pair of fuse clips, said fuse including a tubular casing of insulating material, a .fusible element inside said casing, a pair of terminal caps 'conductively interconnected by said fusible element and mounted .on the ends of said casing, each of said pair'ofjcaps having a cylindrical .contact surface engaged by said, pair of contact surfaces of one of said pair of clips,- an annular end surface, a cylindrical projection extending axially outwardly from said annular end surface, and a circular end surface closing the axially outer end of said cylindrical projection, each of said pair of caps consisting of one single seamless .piece of sheet metal, the axial spacing of the annular end surface of each of said pairof caps being slightly less than said predetermined axial spacing of said I pair of rejection abutments of said pair of clips allowing said pair of rejection abutments of said pair of clips to overlap said annular end surface of each of said pair of caps, and the diameter of said cylindrical projection of each of said pair of caps being smaller than the diameter of said cylindrical contact surfaceand sufficiently small to allow insertion of said fuse into said pair of clips without interference of said cylindrical projection of each of said pair of caps with said pair of rejection abutments of said pair of clips. 7

2. A rejection-type fuse clip and fuse assembly as specified in claim I wherein said casing and said cylindrical projection of one of said pair of caps is filled with a pulverulent arcquenching filler, and wherein said cylindrical projection of the other pair of caps defines a void, said void being separated by a partition from said pulverulent aroquenching filler inside of said casing.

3. A rejection-type fuse clip and fuse assembly as specified in claim I wherein said casing and said cylindrical projection of one of said pair of caps is filled with a pulverulent arcquenching filler, and wherein the other of said cylindrical projection of the other of said pair of caps is filled with a solidified insulating material precluding said pulverulent arc-quenching filler and products of arcing from entering into said cylindrical projection of said other of said pair of caps.

4. A rejection-type fuse clip and fuse assembly as specified in claim 1 wherein each of said pair of fuse clips has a pair of spaced juxtaposed surfaces, one of said pair of surfaces engaging said cylindrical contact surface of one of said pair of caps and the other of said pair of surfaces engaging said cylindrical projection of one of said pair of caps, said other of said pair of surfaces having a pair of edges narrowly spaced from said annular end surface of one of said pair of caps.

5. An electric high interrupting capacity cartridge fuse including a. a tubular casing of insulating material;

. a pair of substantially annular adapters each frictionally mounted on said cylindrical projection of one of said pair of terminal caps, each of said pair of annular adapters having an inner diameter substantially equal to the outer diameter of saidcylindrical projection of each of said pair of terminal caps and each of said pair of annular adapters having an outer diameter substantially equal to the outer diameter of said axially inner surface of each of said pair of caps.

An electric high interrupting capacity cartridge fuse as specified in claim wherein each of said pair of annular adapsaid , ters extends in a direction longitudinally of said casing beyond cylindrical projection of each of said pair of terminal caps to adapt said cartridge fuse for insertion into a pair of fuse clips having a spacing exceeding the spacing between said cylindrical projection of each of said pair of terminal caps.

In a rejection-type fuse and fuse clips assembly the combination of a cartridge fuse including a tubular casing of insulating material, a fusible element inside said casing, a pair of terminal caps conductively interconnected by said fusible element, each of said pair of terminal caps having an axially inner cylindrical portion of relatively large diameter overlapping one of the ends of said casing, an axially outer cylindrical portion of relatively small diameter closed by a circular end surface and an annular end surface intermediate said axially inner portion and said axially outer portion, each of said pair of caps consisting of one single, seamless piece of sheet metal; and a pair of spaced fuse clips each having a pair of contact surfaces in engagement with said axially inner cylindrical portion of one of said pair of terminal caps and each of said pair of fuse clips having a pair of rejection abutments overlapping said annular end surface of one of said pair of terminal caps and having a relatively small axial clearance from said annular end surface of one of said pair of terminal caps, and said pair of contact surfaces of each of said pair of fuse clips having a relatively large radial clearance from said axially outer portion of one of said pair of terminal caps.

8. In a rejection-type fuse and fuse clip assembly the combination of a. a cartridge fuse including a tubular casing of insulating material, a fusible element inside said casing, a pair of terminal caps conductively interconnected by said fusible element, at least one of said, pair of terminal caps having an axially inner cylindrical portion of relatively large diameter overlapping one of the ends of said casing, an

axially outer cylindrical portion of relatively small diameter closed by a circular end surface and an annular end surface intermediate said axially inner portion and said axially outer portion, said one of said pair of terminal caps consisting of one single, seamless piece of sheet metal; and

. a pair of spaced fuse clips each having a pair of contact surfaces in engagement with one of said pair of terminal caps, said pair of contact surfaces of at least one of said pair of fuse clips being in engagement with said axially inner cylindrical portion of said one of said pair of terminal caps, said one of said pair of fuse clips having a pair of rejection abutments overlapping said annular end surface of said one of said pair of terminal caps and having a relatively small axial clearance from said annular end surface of said one of said pair of terminal caps, and said pair of contact surfaces of said one of said pair of fuse clips having a relatively large radial clearance from said axially outer portion of said one of said pair of terminal caps. 

1. A rejection-type fuse clip and fuse assembly including a. a pair of spaced fuse clips each having a pair of fuse-capengaging contact surfaces, each of said pair of fuse clips further including a pair of rejection abutments, each of said pair of rejection abutments projecting radially inwardly from one of said pair of contact surfaces, each of said pair of rejection abutments having a smaller radial spacing than the radial spacing of said pair of contact surfaces, and said pair of rejection abutments of said pair of clips having a predetermined axial spacing; and b. an electric high interrupting capacity cartridge fuse inserted into said pair of fuse clips, said fuse including a tubular casing of insulating material, a fusible element inside said casing, a pair of terminal caps conductively interconnected by said fusible element and mounted on the ends of said casing, each of said pair of caps having a cylindrical contact surface engaged by said pair of contact surfaces of one of said pair of clips, an annular end surface, a cylindrical projection extending axially outwardly from said annular end surface, and a circular end surface closing the axially outer end of said cylindrical projection, each of said pair of caps consisting of one single seamless piece of sheet metal, the axial spacing of the annular end surface of each of said pair of caps being slightly less than said predetermined axial spacing of said pair of rejection abutments of said pair of clips allowing said pair of rejection abutments of said pair of clips to overlap said annular end surface of each of said pair of caps, and the diameter of said cylindrical projection of each of said pair of caps being smaller than the diameter of said cylindrical contact surface and sufficiently small to allow insertion of said fuse into said pair of clips without interference of said cylindrical projection of each of said pair of caps with said pair of rejection abutments of said pair of clips.
 2. A rejection-type fuse clip and fuse assembly as specified in claim 1 wherein said casing and said cylindrical projection of one of said pair of caps is filled with a pulverulent arc-quenching filler, and wherein said cylindrical projection of the other pair of caps defines a void, said void being separated by a partition from said pulverulent arc-quenching filler inside of said casing.
 3. A rejection-type fuse clip and fuse assembly as specified in claim 1 wherein said casing and said cylindrical projection of one of said pair of caps is filled with a pulverulent arc-quenching filler, and wherein the other of said cylindrical projection of the other of said pair of caps is filled with a solidified insulating material precluding said pulverulent arc-quenching filler and products of arcing from entering into said cylindrical projection of said other of said pair of caps.
 4. A rejection-type fuse clip and fuse assembly as specified in claim 1 wherein each of said pair of fuse clips has a pair of spaced juxtaposed surfaces, one of said pair of surfaces engaging said cylindrical contact surface of one of said pair of caps and the other of said pair of surfaces engaging said cylindrical projection of one of said pair of caps, said other of said pair of surfaces having a pair of edges narrowly spaced from said annular end surface of one of said pair of caps.
 5. An electric high interrupting capacity cartridge fuse including a. a tubular casing of insulating material; b. a fusible element inside said casing; c. a pair of terminal caps conductively interconnected by said fusible element mounted on the ends of said casing, each of said pair of caps having a cylindrical axially inner surface, an annular end surface, a cylindrical projection extending axially outwardly from said annular end surface, and a circular end surface closing the axially outer end of said cylindrical projection; and d. a pair of substantially annular adapters each frictionally mounted on said cylindrical projection of one of said pair of terminal caps, each of said pair of annular adapters having an inner diameter substantially equal to the outer diameter of said cylindrical projection of each of said pair of terminal caps and each of said pair of annular adapters having an outer diameter substantially equal to the outer diameter of said axially inner surface of each of said pair of caps.
 6. An electric high interrupting capacity cartridge fuse as specified in claim 5 wherein each of said pair of annular adapters extends in a direction longitudinally of said casing beyond said cylindrical projection of each of said pair of terminal caps to adapt said cartridge fuse for insertion into a pair of fuse clips having a spacing exceeding the spacing between said cylindrical projection of each of said pair of terminal caps.
 7. In a rejection-type fuse and fuse clips assembly the combination of a. a cartridge fuse including a tubular casing of insulating material, a fusible element inside said casing, a pair of terminal caps conductively interconnected by said fusible element, each of said pair of terminal caps having an axially inner cylindrical portion of relatively large diameter overlapping one of the ends of said casing, an axially outer cylindrical portion of relatively small diameter closed by a circular end surface and an annular end surface intermediate said axially inner portion and said axially outer portion, each of said pair of caps consisting of one single, seamless piece of sheet metal; and b. a pair of spaced fuse clips each having a pair of contact surfaces in engagement with said axially inner cylindrical portion of one of said pair of terminal caps and each of said pair of fuse clips having a pair of rejection abutments overlapping said annular end surface of one of said pair of terminal caps and having a relatively small axial clearance from said annular end surface of one of said pair of terminal caps, and said pair of contact surfaces of each of said pair of fuse clips having a relatively large radial clearance from said axially outer portion of one of said pair of terminal caps.
 8. In a rejection-type fuse and fuse clip assembly the combination of a. a cartridge fuse including a tubular casing of insulating material, a fusible element inside said casing, a pair of terminal caps conductively interconnected by said fusible element, at least one of said pair of terminal caps having an axially inner cylindrical portion of relatively large diameter overlapping one of the ends of said casing, an axially outer cylindrical portion of relatively small diameter closed by a circular end surface and an annular end surface intermediate said axially inner portion and said axially outer portion, said one of said pair of terminal caps consisting of one single, seamless piece of sheet metal; and b. a pair of spaced fuse clips each having a pair of contact surfaces in engagement with one of said pair of terminal caps, said pair of contact surfaces of at least one of said pair of fuse clips being in engagement with said axially inner cylindrical portion of said one of said pair of terminal caps, said one of said pair of fuse clips having a pair of rejection abutments overlapping said annular end surface of said one of said pair of terminal caps and having a relatively small axial clearance from said annular end surface of said one of said pair of terminal caps, and said pair of contact surfaces of said one of said pair of fuse clips having a relatively large radial clearance from said axially outer portion of said one of said pair of terminal caps. 